Handheld, electronic video game devices are commercially available from many manufacturers. Very high sales volume of these devices and competition among manufacturers, distributors, and retailers has driven prices for these devices to a level that is very low compared to other electronic products of similar complexity where the sales volume and competition are not as great.
The handheld game devices are packaged and sold in two components, a host display and an interchangeable memory cartridge. The memory cartridge connects to the host display to give the appearance of a single, packaged unit with a volume in the range of 250 to 2500 cubic centimeters. Typically, a user purchases one host display and multiple memory cartridges, depending upon how many games he likes and can afford.
Existing host displays have a user interface including keys, a liquid crystal display, and a speaker so that a user can play a game, and have a device interface to a second game device so that two or more users can play a game with or against each other. The memory cartridge includes a memory storage device to store pre-coded software that includes the data and program instructions for the user interface and the game. A processing system in the host display, including a microprocessor, memory, and associated logic hardware, operates electrical data, address, and control lines in a conventional manner to interface the elements in the host display, the memory cartridge, and the second game device.
Hundreds of games are available for recreation, such as games in which the object is to stop space monsters from destroying the earth, and for education, such as games in which the object is to learn multiplication tables. The long term strategy adopted by the manufacturers of the game devices is to sell the host display at a very low price relative to the cost of manufacturing the host display and to make their profit by selling memory cartridges at a higher price relative to the cost of manufacturing the memory cartridge. Since the price of the game device is low to start with, the result of this strategy is that the price of the host display is very low compared to other electronic products.
The manufacturers of the electronic, handheld video game devices and the game software development companies make arrangements to share the profit generated by selling the memory cartridges. To prevent pirate organizations from developing games and manufacturing and/or distributing memory cartridges and not sharing the profit, the game device manufacturers employ a secret security key. Many security key systems have been developed. In the most common system, a character or a set of characters are pre-coded and stored in memory in the host display and a second character or set of characters are pre-coded and stored in the memory storage device in the memory cartridge. When the game is initiated and optionally at times while the user is playing the game, the instructions in the pre-coded software in the memory cartridge and/or in the host display compare the character or characters in the host display and to the character or characters in the memory cartridge to check for a match or other pre-determined relationship. If the characters do not match or relate in the proper manner, the game will terminate. Many workers in the field have described security technology for this purpose. Okada in U.S. Pat. No. 5,134,391 discloses a system in which the processing system in the host display looks for a match between characters stored in the host display and characters stored in the memory cartridge. If a match is found the game can commence, otherwise the game is inhibited.
The device interface in the host display interconnects two or more game devices, where each game device has a memory cartridge, so that two or more users can play a game with or against each other. Existing device interfaces use cabled connections with serial electrical signals. When interconnected, the results shown on the display of one game device depend, in part, upon events in the other game device. For two or more users to play, the software in the memory storage device must be pre-coded with the capability to receive and send information over the device interface.
Printed map and printed yellow page technologies exist entirely separate from game technology. Printed maps are available for almost all features that have geographical locations. Printed yellow pages, which are now available from sources other that the local phone company, are available for information on goods and services that are provided by establishments of many types. A user of maps and/or yellow pages is usually most interested in the information on the features and/or goods and services that are near to his present position, to a planned route, or to a destination. To find the information in which he is most interested, the user must sort through all the information available. A limitation of printed maps and printed yellow pages is that the user must manually sort all the information on the features and/or goods and services in order to find the information that is relevant to his location. A further limitation of printed maps and printed yellow pages is that the user must re-sort all the information on the features and/or goods and services in order to find the information that is relevant to his location each time he travels or is traveling to a new location.
Recently, electronic processing systems and displays have begun to replace paper in some applications. For example, facsimile transmission and files stored in the memory of computer systems have begun to replace post mail and files stored in manila envelopes. Electronic map technology exists to replace paper maps where an electronic map database is stored in memory storage devices as a bit map or raster where data stored sequentially in memory represent the intensity and/or color of sequential pixels of a map or as vectors where data in memory represent the coordinates and intensity and/or color of pixels of a map. The map database may also store characters that are superimposed on the display of the map where characters are in ASCII or a similar format. Multiple color or gray scales require additional data stored in memory for each pixel. Raster maps are easier to develop and less likely to have errors but vector maps can be compressed into less memory and are more easily sorted for features. A combination of raster, vector, and character mapping may be used. Electronic yellow pages technology exists where yellow pages databases including the same or similar goods and services as found in a traditional printed yellow pages in a telephone book are stored in memory storage devices. Yellow pages databases can be stored as a raster, vectors, or characters, or can be stored as a combination of a raster, vectors, and characters. Where the map or yellow pages database is too large for the memory storage device, the database may be divided into a plurality of modules, sometimes overlapping. An electronic display such as a liquid crystal display (LCD), electroluminescent (EL), cathode ray tube (CRT), or other similar electronic technology is used to display the map or yellow pages to the user. A limitation of electronic maps and electronic yellow pages is that the cost of the electronics is substantially greater than the cost of printed paper used for printed maps or printed yellow pages.
Geocoding technology exists to assign location coordinates such as latitude and longitude, latitude, longitude, and altitude, or other coordinate system to an object such as feature on a map or an address in the yellow pages. Geocoding can be used with electronic maps and/or yellow pages so that a user could electronically sort the map and/or yellow pages for information on the features and/or goods and services that are closest to his location. A limitation of geocoded electronic maps and/or yellow pages is that the user must know the coordinates of his present location for the geocoded information to be useful.
Many location determination systems are available or have been proposed to provide location information to a user equipped with a location determination receiver. These receivers include antennas for receiving signals. Ground location determination systems, such as Loran, Omega, TACAN, Decca, U.S. Airforce Joint Tactical Information Distribution System (JTIDS Relnav), or U.S. Army Position Location and Reporting System (PLRS) use the intersection of hyperbolic surfaces to provide location information. A representative ground system is LORAN-C discussed in LORAN-C User Handbook, Department of Transportation, U.S. Coast Guard, Commandant Instruction M16562.3, May 1990, which is incorporated by reference herein. LORAN-C provides a typical location accuracy of approximately 400 meters. A limitation of a LORAN-C location determination system is that not all locations in the northern hemisphere and no locations in the southern hemisphere are covered by LORAN-C. A second limitation of LORAN-C is that the typical accuracy of approximately 400 meters is insufficient for many applications. A third limitation of LORAN-C is that weather, local electronic signal interference, poor crossing angles, closely spaced time difference hyperbolas, and skywaves frequently cause the accuracy to be significantly worst than 400 meters.
Other ground location determination devices are based on systems that were developed primarily for communications such as cellular telephone, FM broadcast, and AM broadcast. Some cellular telephone systems provide estimates of location, using comparison of signal strengths from three or more sources. FM broadcast systems having subcarder signals can provide estimates of location by measuring the phase of the signal. FM subcarrier signals are received from three FM radio stations with known locations but unknown relative phases by a mobile location determination receiver and by a fixed station having a known location. The fixed station determines the relative phases of the signal transmitted by the three FM radio stations and transmits these relative phase information to the location determination receiver. The location determination receiver processes this relative phase information together with the relative phases that it measures to compute its location. A limitation of cellular systems and FM subcarder systems for location determination is that they are limited to small regions, with diameters of the order of 20-50 km.
Satellite location determination systems such as Global Positioning System, GPS, and the Global Orbiting Navigational System, GLONASS, use the intersection of spherical surface areas to provide location information with accuracy typically within 100 meters anywhere on or near the surface of the earth. The satellite location determination systems include satellites having signal transmitters to broadcast location information and control stations on earth to track and control the satellites. Location determination receivers process the signals transmitted from the satellites and provide location information to the user.
The Global Positioning System (GPS) is part of a satellite navigation system developed by the United States Defense Department under its NAVSTAR satellite program. A fully operational GPS includes up to 24 satellites approximately uniformly dispersed around six circular orbits with four satellites each, the orbits being inclined at an angle of 55.degree. relative to the equator and being separated from each other by multiples of 60.degree. longitude. The orbits have radii of 26,560 kilometers and are approximately circular. The orbits are non-geosynchronous, with 0.5 sidereal day (11.967 hours) orbital time intervals, so that the satellites move with time relative to the Earth below. Theoretically, four or more GPS satellites will be visible from most points on the Earth's surface, and visual access to three or more such satellites can be used to determine an observer's position anywhere on the Earth's surface, 24 hours per day. Each satellite carries a cesium or rubidium atomic clock to provide timing information for the signals transmitted by the satellites. Internal clock correction is provided for each satellite clock.
A second configuration for global positioning is the Global Orbiting Navigation Satellite System (GLONASS), placed in orbit by the former Soviet Union and now maintained by the Russian Republic. GLONASS also uses 24 satellites, distributed approximately uniformly in three orbital planes of eight satellites each. Each orbital plane has a nominal inclination of 64.8.degree. relative to the equator, and the three orbital planes are separated from each other by multiples of 120.degree. longitude. The GLONASS circular orbits have smaller radii, about 25,510 kilometers, and a satellite period of revolution of 8/17 of a sidereal day (11.26 hours). A GLONASS satellite and a GPS satellite will thus complete 17 and 16 revolutions, respectively, around the Earth every 8 days. The signal frequencies of both GPS and GLONASS are in L-band (1 to 2 GHz).
Since the signals from the satellites pass through the tropospheric for only a short distance, the accuracy of satellite location determination systems such as GPS or GLONASS is largely unaffected by weather or local anomalies. Due to the high frequencies used and the attenuation caused by the great distance over which the signals must travel, a limitation of satellite determination systems is that the location determination receiver must be in line of sight to the satellites in order to receive the satellite signals. A further limitation of GLONASS is that it is not clear that the Russian Republic has the resources to complete and to maintain the system for full world wide 24 hour coverage.
GPS is used by many professionals engaged in navigation and surveying fields such as marine navigation, aircraft piloting, seismology, boundary surveying, and other applications where accurate location is required or where the cost of GPS is small compared to the cost of a mistake in determining location. Some professionals engaged in mobile fields such as utilities, insurance, ranching, prospecting, ambulance driving, trucking, delivery, police, fire, real estate, forestry, and other mobile applications use GPS to save time in their work. GPS is also used for personal travel such as hiking, biking, horseback riding, yachting, fishing, driving in personal cars, and other travel activities. However, most mobile professional and personal users of GPS find that location coordinates as provided by GPS are of limited use unless the map features and/or yellow pages addresses they are using are also located in the same coordinate system. GPS products exist that combine a GPS location determination receiver, an electronic map and/or electronic yellow pages, and geocoding in order to relate the users location to geographical features and/or addresses of goods and services but these products are not mobile and are expensive. Since the market size for navigation and surveying professionals is not large, GPS products have not achieved the manufacturing and distribution volume required to drive costs of the products low enough to attract the majority of mobile professionals and personal travelers.
What is needed is a handhold apparatus that provides a mobile professional or personal traveler user the locations of map features and/or yellow page establishments that are nearby or proximate to his own location. In order to find acceptance in the mobile professional and personal markets, the apparatus must be affordable.